Four people have been killed in Cairo during protests to mark the first anniversary of the Rabaa crackdown in which at least 1,000 people died.

The protesters were shot dead as Egyptian security forces on Thursday dispersed hundreds of supporters of the ousted president, Mohamed Morsi, who had blocked several highways and roads in Cairo and Giza.

It was the first anniversary of the violent Rabaa al-Adawiya and Nahda Square sit-ins last year.

Human Rights Watch released a report on Tuesday that said last years' killings at the two protest camps were crimes against humanity.

HRW called for an international inquiry, urging the United Nations to look into six incidents involving killings of protesters by security forces.

Kenneth Roth, executive director of the New York-based rights group, and HRW Middle East director Sarah Leah Whitson, were denied entry into the country on Monday.

Egypt's government said the report was "characterised by negativity and bias" and relied on anonymous witnesses rather than neutral sources.

Source: Al Jazeera